A battery energy storage system may solve the problems of the randomness and fluctuation of power generation with new energy and electric car charging, may realize the smooth output of power generation with new energy, and can effectively adjust changes in the voltage, frequency and phase of a power grid caused by power generation with new energy and electric car charging. A battery energy storage system in the related art comprises an energy Management system (EMS), a power conversion system (PCS) and an energy storage unit, wherein the PCS comprises a power conversion part and a controller connected to each other by a switch device, and the energy storage unit comprises a battery pack and a battery Management system (BMS) connected to each other via a power wire.
In the related art, for convenience of placement, repair and maintenance of a battery, an energy storage unit is implemented by a battery power cabinet, a standard mounting structure is arranged in the battery power cabinet, and a power wire and a battery interface are deployed, such that a battery module is pluggable. In the related art, a plurality of battery power cabinets are connected to form an array, thereby implementing an energy storage unit in a battery energy storage system.
However, inventors have found that, when a certain battery power cabinet in a battery power cabinet array in the related art fails, the entire battery energy storage system needs to stop running, and thus the needs of system reliability cannot be matched.